Exercise 9: Renal System Physiology: Activity 3: Renal Response to Altered Blood Pressure Lab Report Pre-lab Quiz Results You scored 100% by answering 4 out of 4 questions correctly. 1. If all other variables are kept constant, how does the afferent afferent arteriole radius affect the rate of glomerular filtration filtration (select all that apply)? You correctly answered: c. An increased afferent arteriole arteriole radius will increase the rate of glomerular filtration. d. A decreased afferent arteriole radius will decrease the rate of glomerular filtration. 2. If all other variables are kept constant, how does the efferent efferent arteriole radius affect the rate of glomerular filtration filtration (select all that apply)? You correctly answered: a. An increased efferent arteriole arteriole radius will decrease the rate of glomerular filtration. b. A decreased efferent arteriole radius will increase the rate of glomerular filtration. 3. If all other variables are kept constant, how does blood pressure pressure affect the rate of glomerular filtration (select all that apply)? You correctly answered: b. If blood pressure goes up, the rate of glomerular filtration filtration goes up. d. If blood pressure goes down, the rate of glomerular filtration goes down. 4. In the absence of other renal processes (including tubular reabsorption and secretion), secretion), more glomerular glomerular filtration leads to a larger urine volume. You correctly answered: a. true
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Experiment Results Predict Question: Predict Question: What will happen to the glomerular capillary pressure rate and glomerular filtration rate if both of these arteriole radii changes are implemented simultaneously with the low blood pressure condition? Your answer : c. Glomerular filtration rate and pressure will only increase to the levels measured in the constricted efferent arteriole experiment. Stop & Think Questions: If blood pressure were to drop (for example, as the result of blood loss), what changes in the nephron would allow the kidney to maintain its normal glomerular filtration rate (select all that apply)? You correctly answered: a. afferent arteriole dilation d. efferent arteriole constriction Comparing the glomerular filtration rate and glomerular capillary pressure with the baseline values (from the first run), how effective was the increased afferent arteriole radius in compensating for the low blood pressure? You correctly answered: c. The afferent arteriole dilation returned the l ow glomerular capillary pressure and filtration rate almost to baseline values. Comparing the glomerular filtration rate and glomerular capillary pressure with the baseline values (from the first run), how effective was the decreased efferent arteriole radius in compensating for the low blood pressure? You correctly answered: b. The efferent arteriole constriction improved the low gl omerular capillary pressure and filtration rate marginally. Experiment Data: Afferent Radius (mm) 0.50 0.50 0.60 0.50 0.60
Efferent Radius (mm) 0.45 0.45 0.45 0.35 0.35
Beaker Press. (mm Hg) 90 70 70 70 70
Glomerular Press. (mm Hg) 55.08 49.72 54.25 51.24 55.58
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Glom. Filt. Rate (ml/min) 124.99 58.57 114.72 77.41 131.15
Urine Volume (ml) 200.44 161.76 196.72 231.12 245.57
Post-lab Quiz Results You scored 100% by answering 4 out of 4 questions correctly. 1. If all other variables are kept constant, when blood pressure decreases, glomerular filtration You correctly answered: c. decreases. 2. If afferent arteriole radius decreases in response to an increase in blood pressure, then glomerular filtration You correctly answered: b. remains approximately the same. 3. If all other variables are kept constant, when the efferent arteriole radius decreases, glomerular filtration You correctly answered: a. increases. 4. With blood pressure held at a constant value, which of the following combinations will raise the glomerular filtration rate above baseline values? You correctly answered: b. afferent arteriole dilation and efferent arteriole constriction
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Review Sheet Results 1. List the several mechanisms you have explored that change the glomerular filtration rate. How does each mechanism specifically alter the glomerular filtration rate? Your answer: si se da por separado: -El aumento del radio de la arteriola aferente y la disminución del radio de la arteriola eferente . En ambos casos se produce un aumento en la tasa de filtración glomerular. -Si se da simultáneamente: -El aumento del radio de la arteriola aferente y la disminución del radio de la arteriola eferente , en este experimento provocó un aumento leve en la tasa de filtración glomerular. 2. Describe and explain what happened to the glomerular capillary pressure and glomerular filtration rate when both arteriole radii changes were implemented simultaneously with the low blood pressure condition. How well did the results compare with your prediction? Your answer: El aumento del radio de la arteriola aferente y la disminución del radio de la arteriola eferente , en este experimento provocó un aumento en la tasa de filtración glomerular. en el caso de la presion del capilar glomerular, ambas aumentaron muy poco. 3. How could you adjust the afferent or efferent radius to compensate for the effect of reduced blood pressure on the glomerular filtration rate? Your answer: Incrementando el radio ede la arteriola aferente y disminuyendo el radio de la arteriola eferente . esto me permitiría compensar la presión baja de la sangre . y aSÍ regular la tasa de filtración glomerular. 4. Which arteriole radius adjustment was more effective at compensating for the effect of low blood pressure on the glomerular filtration rate? Explain why you think this difference occurs. Your answer: El incremento del radio de la arteriola aferente tiene un mejor efecto que la disminución del radio de la arteriola eferente porque la presión capilar glomerular es mas próxima a la presión normal.
La disminución del radio de la arteriola eferente evita la salida normal de sangre, la sangre avanza mas lento, desde el glomérulo, lo que ocasiona un aumento leve de la presión en el interior del glomérulo y un mayor volumen de filtrado (orina).
5. In the body, how does a nephron maintain a near-constant glomerular filtration rate despite a constantly fluctuating blood pressure? Your answer: mecanismos tanto internos como externos podrían afectar , así como la capacidad que tiene la nefrona de ajustar o desajustar los radios de las arteriolas para que la tasa de filtracion y las otras cantidades se mantengan cerca a los valores constantes.
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